1. Technical Field of the Invention
The present invention relates to an optical disc apparatus and particularly to a technique for chucking an optical disc.
2. Description of the Related Art
Techniques relating to the present invention are disclosed in, e.g., Japanese Patent Laid-open Nos. 2005-85449 and 2002-352498. Japanese Patent Laid-open No. 2005-85449 discloses a disc drive wherein a bent piece 102 on the side of a bottom case 4 is formed with a vertical slit 103 adapted to engage and support a pivot shaft (second pivot shaft) 105 secured to a base (base of a unit mechanism portion) 31. In Japanese Patent Laid-open No. 2002-352498 discloses a disc drive wherein a traverse (unit mechanism portion) 30 is raised and lowered under positional control by a first cam mechanism 41, a second cam mechanism 51 and a third cam mechanism 52. The first cam mechanism 41 is configured such that a cam pin 36 fixed to a base member (base member of the unit mechanism portion) 16 is slidably engaged with a slot formed in the surface of a main slider 40. The second cam mechanism 51 is configured such that a cam pin 37 fixed to the base member (base member of the unit mechanism portion) 16 is slidably engaged with a slot formed in the surface of a sub-slider 50 disposed nearly perpendicularly to the main slider 40. The third cam mechanism 52 is configured such that a cam pin 53 fixed to the base member (base member of the unit mechanism portion) 16 is slidably engaged with two slots of the same shape formed in both ends of the sub-slider 50.
However, of the conventional techniques described in the above patent documents, the technique described in Japanese Patent Laid-open No. 2005-85449 is considered such that the vertical slit 103 adapted to engage the pivot shaft (second pivot shaft) 105 is uniform in width. Thus, the construction disclosed therein is not a construction wherein the position restriction in the disc plane direction of the pivot shaft (second pivot shaft) 105 at a disc chucked height position is eased or cancelled. Therefore, when the center axis of a turntable is offset relative to the center of a center hole (hereinafter referred to as the “disc center hole”) of the disc, the chucking of the disc onto the turntable may be unlikely to be performed in the normal manner. According to the construction disclosed in Japanese Patent Laid-open No. 2002-352498, the first, second and third cam mechanisms are used as cam mechanisms, and the cam pin is engaged with the slot formed in the slider surface. Therefore, the structure of a raising/lowering mechanism having a position restricting function for the traverse (unit mechanism portion) in the disc plane direction is complicated and is liable to increase in size.
In view of the above-mentioned conventional circumstances the problem to be solved by the present invention is to permit a normal chucking operation to be performed in an optical disc apparatus even in the case where the axis of the turntable is offset relative to the disc center hole with a simple, small-sized and thin device configuration.
It is an object of the present invention to solve the above-mentioned problem and provide a technique capable of improving reliability in chucking an optical disc in an optical drive.